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Officials fear spread after first polio case in US in nearly 10 years, and UK cases rise

In America’s first confirmed case of the disease in a decade, an adult resident in New York City, has been diagnosed with polio after experiencing paralysis a month ago, and health authorities fear this could be “just the tip of an iceberg”.

The virus has also been detected in sewage in Rockland County and neighbouring Orange County. The positive samples were genetically linked to the individual case, but no other cases in the US have yet been reported, reports CNN.

Polio was once one of the most feared diseases in the country, with waves of infections disabling about 35 000 people annually in the late 1940s. The first polio vaccine became available in 1955.

Testing of this latest case suggested the highly contagious and long-dreaded virus may have originated outside the country, the New York State Health Department said in a statement, with the county’s health commission Dr Patricia Schnabel Ruppert saying they were “surveying the family and close contacts to assess risks to the community”.

She said the man was unvaccinated, and analysis by state health experts found the case originated from a strain of weakened virus used in oral polio vaccines overseas that can sometimes cause an infection: for that reason, they were discontinued in the United States in 2000.

Now, the country administers an inert polio vaccine administered in three injections, which provides nearly 100% immunity, reports Reuters.

Exactly how or where the infected resident was exposed remains under evaluation, Ruppert said, but he belonged to the Orthodox Jewish community, which was at the centre of a 2018-2019 measles outbreak attributed to relatively low vaccination rates among the highly devout.

The US Centres for Disease Control and Prevention (CDC), which confirmed the polio diagnosis, said no cases of the disease have originated in the US since 1979.

A naturally occurring, or “wild” virus, can also be brought into the country by an infected traveller, as most recently occurred in 1993, with the last known polio infection of any kind being traced to an oral vaccine in 2013, the agency said.

On 6 July, Medicalbrief reported that British health authorities were urgently investigating a rare polio virus discovery in sewage samples in London, potentially putting the UK’s polio-free status at risk for the first time in almost two decades.

A number of waste samples from a sewage treatment works in east London had tested positive for vaccine-derived polio virus between February and May, the UK Health Security Agency (UKHSA) said on 29 June.

Last Wednesday, NPR reported that children aged one-nine in London were eligible for booster doses of a polio vaccine, after health authorities reported found that the virus had spread in multiple areas of the city but found no cases of the paralytic disease in people.

Britain’s Health Security Agency said it had detected viruses derived from the oral polio vaccine in the sewage water of a total of eight London boroughs. The agency’s analysis of the virus samples suggested “transmission has gone beyond a close network of a few individuals”.

Polio is often asymptomatic, but can produce flu-like symptoms like a sore throat, fever, fatigue and nausea, and in rare instances, the virus can invade the nervous system and cause irreversible paralysis.

The patient in the US was diagnosed after experiencing weakness and paralysis about a month ago.

Polio has no cure, but infection can be prevented by vaccination – and a dramatic reduction in cases worldwide in recent decades has been due to intense national and regional immunisation campaigns in babies and children.

CNN said the case in Rockland County, New York, which has “a stunningly low polio vaccination rate”, “is just the tip of the iceberg” and an indication there “must be several hundred cases in the community circulating”, a senior official said.

Dr José Romero, director of the CDC’s National Centre for Immunisation and Respiratory Diseases, said most people with polio don’t have symptoms and so can spread the virus without knowing it.

Romero said the CDC was considering a variety of options to protect people from polio, including offering children in the area an extra shot of the vaccine, as UK health authorities are doing now in London, or recommending extra doses to certain groups of adults.

“We’re looking into all aspects of how to deal with this. At this point, we don’t have a definitive answer,” he said.

 

Reuters article – Polio case found in New York City suburb, first in nearly a decade (Open access)

 

CNN article – ‘Silent’ spread of polio in New York drives CDC to consider additional vaccinations for some people (Open access)

 

NPR article – Polio is found in the U.K. for the first time in nearly 40 years. Here's what it means (Open access)

 

See more from MedicalBrief archives:

 

Polio virus discovery shows we can’t let guard down

 

First polio outbreak in Mozambique in 30 years

 

Seven countries report more vaccine-derived polio cases

 

Malawi declares outbreak following Africa’s first wild polio case in five years

 

 

 

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